3 Aug 2008

The decision’s been made, out came the saw and off came the bottom radiator pipe. The decision was make easier after realizing that there are other radiator modifications that need welding, so what’s one more? To fit the radiator under the nose, the filler cap flange is being replaced with a low-profile water bleeder. (The cooling system will get filled through a header tank back in the engine compartment.) Mounts are also needed, too. All the welding can be done at one time and transform a nearly-impossible-to-work-with-awkward-assembly into something that fits really well. It’ll be well worth the bother.

Worked all day on the front chassis area, probably the most complicated part of the entire design. Kind of like juggling a bowling ball, flaming torch, chicken egg, frog, and a running chainsaw, there’s the nosecone, steering rack, cooling fan, duct-work, and suspension pickup points. It’s easy to deal with these one at a time, dedicating tubes to deal with them separately. It’s about 100 times harder to use one tube to do two or three different tasks at the same time, very tricky! It’ll be worth it – after it’s done – in the form of fewer tubes doing the work. No pictures; it’s just a bunch of half-finished wood pieces at various angles – not much to look at. I plan on taking a week off soon and will dedicate the entire time to finishing the mock-up.

After the mockup’s complete, is the task of getting it into the computer. It’s the only way to force myself not to cheat, taking measurements off the wood and going straight to steel without writing the numbers down. Come to think of it, that’s not all that bad… and might actually be a good idea. If I go to CAD first, then build the steel chassis, I risk following mistakes and wasting material – and forgetting to make the corrections on the CAD drawings. If I build the steel chassis first, then take measurements, it guarantees that what’s there is really what was built, not numbers that were later changed and forgotten about. Hmmm, maybe cutting steel is not as far off as I thought…

2 Aug 2008

Ordered a muffler to make sure there’ll be enough room for it and its associated pipes. Because a turbocharger acts as a muffler, too, a smaller muffler can be used, but since most people will run a normally aspirated engine, I have to save room for a larger unit. Since neither the muffler nor axles are here yet, the rear suspension area is on hold, so attention moves to the front suspension.

Installed the radiator and – as many Locost builders discover – the lower radiator pipe interferes with the steering rack in a big way, like, going right through it. The choices are to move the rack, move the radiator, or move the radiator outlet. Car design is all about compromise, but moving the rack is a really bad idea since it messes up both Ackerman and bumpsteer. Another way to improve clearance is to move the rack (and wheels) back, shortening the wheelbase. It’s currently 96″ and while there’s nothing magic about that number, it gives a warm fuzzy 1.6:1 wheel-to-track ratio. I have to think about it.

Then there’s moving the radiator pipe, and since it’s a big 1.75″ diameter that’s already pointing the wrong direction, it’s very tempting to move it. I’m reluctant to do this because it means builders will have to weld aluminum, or pay to have it done, something I’m trying to avoid. And finally, the nose and radiator can be moved forward to free up space… but I find this solution offensive, lengthening the entire car by 4″ just to avoid one aluminum weld. I just can’t bring myself to do that.

30 Jul 2008

Ordered the axles, knowing that if I mess up (like when building Kimini) they’re going to be worth exactly zero if they don’t fit, due to them being for my quirky one-of-a-kind application. However, I double and triple-checked the numbers so it’s time to get on with things.

Hanging out on the various Honda and Acura sites sometimes pays off in the form of good deals. Picked up an adjustable fuel pressure regulator, braided fuel lines, fuel rail, 750cc injectors and clips, and a throttle-body. The throttle-body is needed because some late-model engines – like this one – are “drive by wire.” The throttle body doesn’t have a throttle position sensor because the computer knows the position it drove it to. Taking the stepper motor off is easy, but now the aftermarket ECU can’t know throttle plate position. The solution is to substitute a throttle-body (and an engine wire harness) from a similar model that uses a traditional cable-operated throttle.

Oh, and good news on the twin-disc clutch – it’s fine. That’s a relief.